Vertical hammer mill discharge



March 21, 1944. H. H. HARRIS VERTICAL HAMMERMILL DISCHARGE Filed Dec. 51, 1940 INVENTGR. AIP/JYHHARR/s QJ @.GAYb/V% A T TOP/HEY.

Patented Mar. 21, 1944 VERTICAL HAMMER DIILL DISCHARGE Harry E. Harris, Palo Alto, Calif., asslgnor to Enterprise Engine & Foundry Company, San Francisco, Calif., a corporation of California Application December 31, 1940, Serial No. 372,621

2 Claims.

This invention relates to vertical hammer mills of the type having a screen through which the iinely disintegrated material passes before being discharged from the mill, and has to do with improvements at the discharge end of the mill.

The object of the invention is to provide improvements in a vertical hammer mill of the type mentioned whereby the finished and screened product of the mill will be guided away separately from the unscreened or rejected products which would not pass through the screen.

In the accompanying drawing- Fig, 1 is a vertical cross section of the body of a vertical hammer mill showing my improvement as seen from the line li of Fig. 2, and omitting the upper part and driving connections of the mill.-

Fig. 2 is a horizontal cross section of the mill as seen from the line 2-2 of Fig. 1.

Fig. 3 is a separate side view of the two discharge chutes of Fig. 1 showing them in elevation and in the relative position occupied when attached to the mill as shown in Fig. 1.

The mill shown to illustrate the improvement is of the well known type wherein a vertical shaft carrying a series of radially projecting beater arms or hammers revolves within a cylindrical screen to beat up or disintegrate any desired material fed to the rotor at the upper end of the screen to .all by gravity past the rotors beater arms or hammers to be struck thereby and disintegrated so that the line particles are hurled through the screen for discharge from a confined space outside the screen, while any rejects or unbroken pieces of the feed material pass downwardly through the rotor or space enclosed by the cylindrical screen.

The features above described are all very old in the art and are shown in the accompanying drawing as follows: i is the vertical rotor shaft driven from any source of power not shown, 2 are the beater arms or hammers projecting from hubs 3 suitably secured to the shaft, and which arms may be of any length, shape, and either rigid or pivotally connected to their-hubs as well understood in the art. 4 designates the lower bearing supported by a spider casting l4, rotatably supporting the rotor shaft (the upper bearing not being shown), 5 is a stationary cylindrical screen surrounding the beater arms or rotor, 6 is an outer casing secured around the frame 1 of the mill to form a space into which the material hurled through the screen falls and passes out through openings in the mill frame at the lower end as indicated by the arrows.

Any material not reduced by the beater arms of course passes out of the frame openings at the lower end of the screen, and would mix with the already ground and screened product unless partition means of some kind were provided to prevent it, and which means illustrated in the drawing comprises the invention.

In the drawing the screened material falls downward through frame openings 8 out of a discharge chute ll secured to the margin of the mill frame I as by bolts l5, while the rejects from the lower end of the rotor fall through an opening in and into discharge chute ll secured to the rim l6 of the bearing spider II as by tap bolts 11, all as indicated by the arrows in Fig. 1.

By a study of the figures it will be seen that the two separate discharge chutes connect respectively with openings in opposite halves of the mill bottom, and the bottom is closed at opposite halves as at l2 and IS, the chutes stand side by side so as to be separately removable. In Fig. 1 they are both shown as funnels broken open to indicate the paths of the materials, and while from the drawing they might both be complete funnels with the smaller one inside the larger one with the discharge pipe of the inner one projecting through the side of the outer one, like the separate discharge arrangement shown in the British Patent #198,582, they would not then -be separately removable.

It is recognized that such a hammer mill as illustrated is really a combined mill and screen, and that in all milling and screening apparatus the screened material always takes a separate path of discharge from the rejects or unscreened material as shown generally in prior U. S. Patents #500,916, 1,262,530, 1,250,590, 1,183,110, 1,433,523, 1,408,303, 1,343,439, and 1,349,739, also British Patent No. 198,582. But my application of the separate discharge chutes to a vertical hammer mill in the manner shown represents an important improvement over the earlier construction, and I therefore claim:

1. In a hammer mill having a vertically disposed disintegrating rotor operating within a stationary cylindrical screen and through which the fines pass, a confined space to the outer side of the screen into which the fines fall, bottom closure means for about half of the lower end of the space embraced by the screen and similarly for the space at the outer sides of the screen and leaving openings at the bottom of the mill respectively at opposite sides of the mill only for separate discharge of the screened material and the rejects not passing through the screen, and

and leaving openings at the bottom of the mill respectively at opposite sides of the mill only for separate discharge of the screened material and the rejects not passing through the screen, and separate discharge chutes connected respectively to said openings to receive the discharge from opposite halves of the mill only said discharge chutes comprising half-round receiving portions with their adjacent vertical walls standing in side 10 by side relation.

HARRY H. HARRIS. 

